Retaining rib and pin for third rail contact shoe



13, 1963 B. MALONEY 3,397,291

RETAINING RIB AND PIN FOR THIRD RAIL CONTACT SHOE Filed Dec. 15, 1966 jmenior fiernard @ang United States Patent 3,397,291 RETAINING RIB AND PIN FOR THIRD RAIL CONTACT SHOE Bernard Maloney, Gary, Ind., assignor to Amsted' Industries Incorporated, Chicago, 111., a corporation of New Jersey Filed Dec. 15, 1966, Ser. No. 602,007 7 Claims. (Cl. 191-49) This invention relates to third rail contact means by which current is taken from a third rail by a car of an electrical railway. More specifically, the present invention constitutes an improvement in parts disclosed in US. Letters Patent No. 2,892,904, issued June 30, 1959, for a Third Rail Contact Shoe.

It has been discovered, after extensive use of the above disclosed invention, that the conventional pin used to hold the electrically conducting wear pad in assembly with the fulcrum member allows loose assembly of the fulcrum and wear plate. This causes wear in the copper shunt and retaining springs; such overall wear allows excessive lateral motion or swivel of the shoe over the third contact rail. This wear leads to poor electrical contact between the various parts, and faulty operation of the electric railway car.

Accordingly, it is an object of this invention to provide a device which will afford positive assembly of the fulcrum and wear pad.

It is a further and more specific object to provide a device which, when assembled with the fulcrum and wear plate, will prevent undue motion of the wear plate with respect to the fulcrum member.

Still another object is to provide an assembly-maintaining device which will inhibit wear in the contact shoe, fulcrum, springs or copper shunt connecting the shoe and fulcrum.

These and other objects and advantages of the invention will become apparent from a consideration of the following specifications and the accompanying drawings, wherein:

FIGURE 1 is a top plan view of a third rail contact shoe and fulcrum embodying a preferred form of my invention;

FIGURE 2 is a side elevational view of the structure shown in FIGURE 1;

FIGURE 3 is a sectional view on line 3-3 of FIG- URE 1;

FIGURE 4 is another sectional view on line 4--4 of FIGURE 1; and

FIGURE 5 is a further sectional view on line 55 of FIGURE 1.

Referring now to FIGURES l and 2, it will be noted that a preferably metallic electrically conductive fulcrum member comprises in part a vertical top flange 12, which flange forms a means of abutment against a convenient portion of an associated car truck (not shown). The fulcrum member 10 may be pivotally mounted as at 14 on a shaft (not shown), said shaft being mounted in suitable fashion on a railway vehicle.

At the opposite end of the fulcrum member 10 and in general extension thereof, is an electrically conductive wear pad member 16, in the general form of a flat plate-like structure. The inboard end of the wear pad 16 comprises a tongue 20, which is accommodated in a longitudinally extending slot 22 formed in the bottom of the fulcrum member 10 and partly defined by a bridge 24 which has a downwardly facing abutment surface 26 on the underside thereof.

The inboard or free end of the tongue is upturned as at 28 to define an upwardly facing spring seat 30 aligned with a downwardly facing spring seat 32 of the fulcrum member 10. One or more compression spring units 34 are compressed by and between the spring seats 30 and 32. A shunt 36 is provided, which prevents any substantial flow of electrical current through the spring units 34.

Inwardly of the fulcrum-end 38, the fulcrum member 10 is formed with a central opening or aperture 40. Into this aperture fits the contact shoe keyway 42, as shown in FIGURES 3 and 5. The shoe keyway 42 is positioned between the shoe tongue 20 and the outboard rail contact portion of the shoe or wear pad 16.

It may then be easily seen how the wear pad 16 is joined to the fulcrum member 10; reference to FIG- URES 4 and 5 will be helpful. The wear pad 16 comprises in part the keyway 42, which is positioned between the sides 44, 46 of the fulcrum member 10. When in the assembled position shown, the opening 48 in the keyway 42 protrudes above the sides 44, 46 of the fulcrum member 10, exposing said keyway 42.

A pin or key 50 is fitted into this keyway 42, as shown in FIGURE 5. The pin rests, at each extremity, upon the sides 44, 46, of the fulcrum member, and supports at its center the keyway 42 attached to the wear pad 16. Small bosses 52, 54 are provided on each of the sides of the fulcrum member 44 and 46, respectively, which serve to retain the pin 50 in its assembled position.

In prior practice, the cross-sectional shape of the retaining pin 50 was considered to be of little importance. Often such pin comprised a semi-circular top, and rectangular bottom, thus conforming to the surfaces which the pin contracted in its assembled position.

I have discovered that pins with such cross-sectional shape do not sufficiently oppose swivel motion of the wear pad, i.e., motion of the Wear pad in a plane parallel to the view plane of FIGURE 1. Such motion may further be envisioned as rotational motion about a substantially vertical axis perpendicular to the wear pad 16 and to the longitudinal axis of the pin 50.

During such swivel motion, the pin 50 maintains more or less rigid contact with the keyway 42, but tends to slide over the side members 44 and 46 of fulcrum member 10.

I have further discovered that small bosses or ribs 55 and 56 placed on the fulcrum member 10 so as to engage the pin 50 near its extremities prevent such motion, As may be seen from FIGURE 1, these bosses serve as pin swivel rotation stops; since the pin rigidly engages the wear pad keyway 42, swivel rotation of the pad 16 itself is materially reduced or prevented, because the pin holds the pad tightly aganst the fulcrum at 55 and 56 (FIGURES 1 and 4).

It will be seen from FIGURE 2 that if the key 50 were circular or semi-circular in form, only the spring assembly 34 would oppose clockwise rotational motion of the wear pad 16 about the key 50 and the keyway 42. In practice, such motion often caused excessive Wear of the key 50, keyway 42 and fulcrum member 10. Use of a key 50 which does not conform to the abutting keyway surface, however, materially reduces this problem. Protrusions or corners formed upon the key, such as those shown on the hexagonal cross-sectional key bite into the keyway 42, affording an interference fit and tending to inhibit such rotation, thus preventing Wear.

Virtually any pin cross-sectional shape which does not conform to the arcuate inner surface of the keyway will bring about these two desirable results. In the illustrations, a preferred hexagonal pin or key is illustrated, but I do not wish to be understood to confine myself to such cross-sectional shape.

A further advantage of a pin design of this nature is that it may be substituted into previously manufactured assemblies of the illustrated type with no modification of the assembly, save the addition of the ribs 55 and 56. This may be easily and inexpensively done by welding or other well-known means. Thus my novel device may be used in either new or old third rail contact shoe assemblies.

As noted briefly above, what is disclosed here is a preferred embodiment of my invention; modifications will be apparent to those skilled in the art. It should be understood that I do not wish to be bound by the exact description given herein.

I claim:

1. In an electrical contact shoe assembly for a vehicle, the combination of a fulcrum having means for attachment to the vehicle, a pad having a bottom surface for engagement with an associated source of electrical current, a tongue on said pad received within a slot of said fulcrum, spring means bearing against upwardly and downwardly facing surfaces of the tongue and fulcrum, respectively, at one side of the slot for urging said pad and fulcrum into interengagement at the opposite side of the slot, a keyway on the pad above the slot, a key extending through the keyway and seated at its ends against upwardly facing surfaces of the fulcrum, said key having line contact with the pad in said keyway and means on the fulcrum for positively locking the key against rotation about its longitudinal axis and about a substantially vertical axis perpendicular to the first-mentioned axis.

2. A device according to claim 1 in which the motion which is inhibited is rotational and occurs about an axis extending longitudinally of the key.

3. A device according to claim 1 wherein said key is formed along its axial length, entirely of intersecting planar surfaces,

4. A device according to claim 3 wherein said'planar surfaces are six in number. Y

5. A device according to claim 4 whereinsaid key is substantially hexagonal in cross-section. c'

6. A device according to claim 1, wherein said means on the fulcrum are protrusions upon the sides of the said slot, and have one side thereof in abutting engagement with the said key.

7. A device according to claim 6, wherein'said means on the fulcrum urges said key into interference fit with said keyway.

References Cited UNITED STATES PATENTS I 2,161,100 6/1939 Sierk 19 149 2,354,885 8/1944 Sierk 19l49 2,892,904 6/1959 Sierk 191-49 DRAYTON E. HOFFMAN, Primary Examiner.

S. T. KRAWCZEWICZ, Assistant Examiner. 

1. IN AN ELECTRICAL CONTACT SHOE ASSEMBLY FOR A VEHICLE, THE COMBINATION OF A FULCRUM HAVING MEANS FOR ATTACHMENT TO THE VEHICLE, A PAD HAVING A BOTTOM SURFACE FOR ENGAGEMENT WITH AN ASSOCIATED SOURCE OF ELECTRICAL CURRENT, A TONGUE ON SAID PAD RECEIVED WITHIN A SLOT OF SAID FULCRUM, SPRING MEANS BEARING AGAINST UPWARDLY AND DOWNWARDLY FACING SURFACES OF THE TONGUE AND FULCRUM, RESPECTIVELY, AT ONE SIDE OF THE SLOT FOR URGING SAID PAD AND FULCRUM INTO INTERENGAGEMENT AT THE OPPOSITE SIDE OF THE SLOT, A KEYWAY ON THE PAD ABOVE THE SLOT, A KEY EXTENDING THROUGH THE KEYWAY AND SEATED AT ITS ENDS AGAINST UPWARDLY FACING SURFACES OF THE FULCRUM, SAID KEY HAVING LINE CONTACT WITH THE PAD IN SAID KEYWAY AND 